I've flown a lot, too. I agree that there's a lot of dreariness involved in air travel. For me, making lists and keeping track of objectives such as these adds a small element of enjoyment.

It definitely matters how one pursues these little objectives. For example, one of mine has been to visit all 50 states in the US. Ten years ago I was at 40/50. I could have made a push for it and ticked off the last 10 in 2-3 years. But that's not how I roll. Ten years later I'm at 48/50. That's because I'm not in it just for box ticking. I've made my visit to each state meaningful by visiting something relevant to business or leisure interest. And I'm not made of money-- or time-- so I haven't been able to do an epic hopscotch across the last several.

In the same vein I also track which US airports I've been to (hence why I follow this thread with interest) but I don't go far out of my way to add to the list. It's more like, if I'm flying from A to B, and I have to take a connection at C, D, or E along the way, I'll pick the itinerary with "E" if I've never been there before and the cost and timing work.